Matthew Berkley was a heavy-set fellow with a red face. He was not particularly proper, but spoke freely and rarely wore a coat. Despite these differences, William Laurence immediately took a liking to him. Berkley was a trustworthy fellow and had been given command of a particularly valuable Regal Copper, Maximus. The two of them had a brotherly sort of relationship, in which they enjoyed teasing and provoking one another.

He had a very loud, booming voice which was lucky, as he rarely had to use a speaking trumpet when aboard his dragon despite Maximus's size.

Berkley was assigned to Maximus's egg almost as soon as it was laid. He waited six years for it to hatch, which is why he was older than most of the new captains.

Although rather brusque, Berkley could also be thoughtful in a blunt way. For example, when Lily, Temeraire and Maximus were all extremely upset after witnessing Jean-Paul Choiseul's execution and its effect on his dragon Praecursoris, it was Berkley who arranged to bring all three dragons and their captains together and get the captains drunk so that everyone could have a good cry and get over it.

He was deeply attached to Maximus and could not keep from crying when Laurence confirmed for him that there might be a cure to the Dragon Plague, as Maximus was suffering greatly. He and Maximus travelled to Cape Town aboard the HMS Allegiance, along with the rest of Lily's formation, to find a cure for the plague.

After Laurence was convicted of treason and Temeraire's crew was disbanded, Berkley took charge of Demane and Sipho, two Xhosa boys whom Laurence had brought from Africa and made runners. Demane was assigned to fly with Arkady, which Berkley considered to be a good assignment for him, as otherwise he tended to get into fights. However, Berkley fought with the Admiralty to keep Sipho in his ground crew, as the boy was not even nine.

Berkley's first name has not been mentioned in any of the books thus far; however, at a Q&A with the author on 7-14-2010, Ms. Novik confirmed that he was named Matthew (barring any missed mentions in the series until that point.)